Particle Party, as Seen from Space

2012 October 25

October 5, 2012 Auroras over North America as Seen from Space. Credit: NASA Earth Observatory.

Some of you may have gotten a show of ‘northern lights’ earlier this month. Here, the northern lights were stretching across Canada’s Quebec and Ontario provinces. Thanks to NASA, we know a bit more about what was really going on up there.

As September was giving way to October on Earth, our Sun was ejecting a mass of energetic particles from its atmosphere. Those particles made it to our atmosphere three days later, causing a stir up in our magnetic field. The collision of solar particles and pressure into our magnetosphere caused particles trapped in the space around Earth to crash down into the upper atmosphere—100 to 400 kilometers / 60 to 250 miles high. When those particles arrived, they excited oxygen and nitrogen molecules and released photons of light. Some of us were able to see this with our own eyes as light danced across the night sky.

NASA satellites track these sun storms as they travel through interplanetary space to the atmosphere of Earth. Northern lights, also known as auroras, are beautiful, but they are not always innocent. They are connected to geomagnetic storms, can distort radio communications (particularly high frequencies), disrupt electric power systems on the ground, and give slight but detectable doses of radiation to flight crews and passengers on high-latitude airplane flights and on spacecraft.

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